The controversial HS2 high-speed railway line will provide Britain's transport system with a heart bypass, Patrick McLoughlin said today.
The Transport Secretary said the UK's transport system was nearly at capacity, telling the Conservative Party Conference in Manchester that the new line linking London to the North would have the same effect as a 12-lane motorway.
He told the conference that he understood opposition to the scheme but said he was confident it could be delivered on time and within its budget.
Mr McLoughlin said it was wrong that passengers could take a high-speed train to the Continent but had to rely on conventional rail to travel to the UK's northern cities.
He said: "The reason we need this new line is that is an essential heart bypass for the clogged arteries of our transport system because the current rail system is almost full and we just haven't got the space that we need for the future.
"The new line will make more room for freight on the railways and take the strain off our roads and it will have the same capacity as a 12-lane motorway.
"I promise you that I hear the critics - boy, do I hear the critics. But I promise you we need a new North-South line to make our country stronger.
"I am from the Midlands and I represent a Derbyshire constituency not far away and I am tired of the moaning London commentators who are pleased enough about the billions we are spending in London on the Crossrail transport system but cannot understand why the rest of the country needs a great transport system too.
"Today, you can get a high-speed train from London to the heart of Europe in Brussels but you can't get one to Birmingham. You can go direct to Lille but you can't go to a city like Leeds - all the way to the Alps if you want but you can't get here to the great city of Manchester by a high-speed train.
"This is bad for our nation and it has got to change."